drivers/rtc/rtc-pl030.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/drivers/rtc/rtc-pl030.c
   4  *
   5  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
   6  */
   7 #include <linux/module.h>
   8 #include <linux/rtc.h>
   9 #include <linux/init.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/amba/bus.h>
  12 #include <linux/io.h>
  13 #include <linux/slab.h>
  14
  15 #define RTC_DR          (0)
  16 #define RTC_MR          (4)
  17 #define RTC_STAT        (8)
  18 #define RTC_EOI         (8)
  19 #define RTC_LR          (12)
  20 #define RTC_CR          (16)
  21 #define RTC_CR_MIE      (1 << 0)
  22
  23 struct pl030_rtc {
  24         struct rtc_device       *rtc;
  25         void __iomem            *base;
  26 };
  27
  28 static irqreturn_t pl030_interrupt(int irq, void *dev_id)
  29 {
  30         struct pl030_rtc *rtc = dev_id;
  31         writel(0, rtc->base + RTC_EOI);
  32         return IRQ_HANDLED;
  33 }
  34
  35 static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  36 {
  37         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  38
  39         rtc_time64_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
  40         return 0;
  41 }
  42
  43 static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  44 {
  45         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  46
  47         writel(rtc_tm_to_time64(&alrm->time), rtc->base + RTC_MR);
  48
  49         return 0;
  50 }
  51
  52 static int pl030_read_time(struct device *dev, struct rtc_time *tm)
  53 {
  54         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  55
  56         rtc_time64_to_tm(readl(rtc->base + RTC_DR), tm);
  57
  58         return 0;
  59 }
  60
  61 /*
  62  * Set the RTC time.  Unfortunately, we can't accurately set
  63  * the point at which the counter updates.
  64  *
  65  * Also, since RTC_LR is transferred to RTC_CR on next rising
  66  * edge of the 1Hz clock, we must write the time one second
  67  * in advance.
  68  */
  69 static int pl030_set_time(struct device *dev, struct rtc_time *tm)
  70 {
  71         struct pl030_rtc *rtc = dev_get_drvdata(dev);
  72
  73         writel(rtc_tm_to_time64(tm) + 1, rtc->base + RTC_LR);
  74
  75         return 0;
  76 }
  77
  78 static const struct rtc_class_ops pl030_ops = {
  79         .read_time      = pl030_read_time,
  80         .set_time       = pl030_set_time,
  81         .read_alarm     = pl030_read_alarm,
  82         .set_alarm      = pl030_set_alarm,
  83 };
  84
  85 static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
  86 {
  87         struct pl030_rtc *rtc;
  88         int ret;
  89
  90         ret = amba_request_regions(dev, NULL);
  91         if (ret)
  92                 goto err_req;
  93
  94         rtc = devm_kzalloc(&dev->dev, sizeof(*rtc), GFP_KERNEL);
  95         if (!rtc) {
  96                 ret = -ENOMEM;
  97                 goto err_rtc;
  98         }
  99
 100         rtc->rtc = devm_rtc_allocate_device(&dev->dev);
 101         if (IS_ERR(rtc->rtc)) {
 102                 ret = PTR_ERR(rtc->rtc);
 103                 goto err_rtc;
 104         }
 105
 106         rtc->rtc->ops = &pl030_ops;
 107         rtc->rtc->range_max = U32_MAX;
 108         rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
 109         if (!rtc->base) {
 110                 ret = -ENOMEM;
 111                 goto err_rtc;
 112         }
 113
 114         __raw_writel(0, rtc->base + RTC_CR);
 115         __raw_writel(0, rtc->base + RTC_EOI);
 116
 117         amba_set_drvdata(dev, rtc);
 118
 119         ret = request_irq(dev->irq[0], pl030_interrupt, 0,
 120                           "rtc-pl030", rtc);
 121         if (ret)
 122                 goto err_irq;
 123
 124         ret = rtc_register_device(rtc->rtc);
 125         if (ret)
 126                 goto err_reg;
 127
 128         return 0;
 129
 130  err_reg:
 131         free_irq(dev->irq[0], rtc);
 132  err_irq:
 133         iounmap(rtc->base);
 134  err_rtc:
 135         amba_release_regions(dev);
 136  err_req:
 137         return ret;
 138 }
 139
 140 static int pl030_remove(struct amba_device *dev)
 141 {
 142         struct pl030_rtc *rtc = amba_get_drvdata(dev);
 143
 144         writel(0, rtc->base + RTC_CR);
 145
 146         free_irq(dev->irq[0], rtc);
 147         iounmap(rtc->base);
 148         amba_release_regions(dev);
 149
 150         return 0;
 151 }
 152
 153 static struct amba_id pl030_ids[] = {
 154         {
 155                 .id     = 0x00041030,
 156                 .mask   = 0x000fffff,
 157         },
 158         { 0, 0 },
 159 };
 160
 161 MODULE_DEVICE_TABLE(amba, pl030_ids);
 162
 163 static struct amba_driver pl030_driver = {
 164         .drv            = {
 165                 .name   = "rtc-pl030",
 166         },
 167         .probe          = pl030_probe,
 168         .remove         = pl030_remove,
 169         .id_table       = pl030_ids,
 170 };
 171
 172 module_amba_driver(pl030_driver);
 173
 174 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 175 MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
 176 MODULE_LICENSE("GPL");